The present invention relates to a magnetic tape apparatus and more particularly to an integrated magnetic tape apparatus including a hand mechanism for taking in and out a cartridge storing a magnetic tape therein and an accessor mechanism for causing the hand mechanism to freely move to a designated position.
Today, a large capacity, integrated magnetic tape apparatus including a hand mechanism and a accessor mechanism is extensively used. Japanese Patent Laid-Open Publication No. 4-20403, for example, discloses a positioning method for positioning the hand mechanisms by use of a bidimensional relative position sensor. The relative position sensor reads a linear scale representative of a position index so as to store the absolute position of the hand mechanism. Another bidimensional relative position sensor is mounted on the hand mechanism for correcting the position of the hand mechanism.
Japanese Patent Laid-Open Publication No. 10-11854 teaches a positioning method using flags. Specifically, flags representative of the addresses of cartridges are arranged in one-to-one correspondence to cells in the lengthwise direction of a magnetic tape apparatus. A board mounted on an accessor mechanism and including a sensor senses the flags for positioning a hand mechanism.
Further, Japanese Patent Laid-Open Publication No. 10-302356 proposes a positioning method using a monodimensional position sensor including reduction optics, a light source and a monodimensional CCD (Charge Coupled Device) in place of the above sensors. The position sensor senses a geometrically patterned address plate.
The problem with the above conventional positioning schemes is that they need sophisticated, bulky arrangements to practice and thereby increases the cost. Moreover, accurate positioning is difficult to achieve with the conventional schemes.
Technologies relating to the present invention are also disclosed in, e.g., Japanese Patent Laid-Open Publication Nos. 4-319564, 5-261684, 7-78401 and 7-101509.